/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.zookeeper.server.util;

import java.io.ByteArrayInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.jute.BinaryInputArchive;
import org.apache.jute.InputArchive;
import org.apache.jute.OutputArchive;
import org.apache.jute.Record;
import org.apache.zookeeper.ZooDefs.OpCode;
import org.apache.zookeeper.server.DataTree;
import org.apache.zookeeper.server.ZooTrace;
import org.apache.zookeeper.txn.CreateSessionTxn;
import org.apache.zookeeper.txn.CreateTxn;
import org.apache.zookeeper.txn.CreateTxnV0;
import org.apache.zookeeper.txn.DeleteTxn;
import org.apache.zookeeper.txn.ErrorTxn;
import org.apache.zookeeper.txn.SetACLTxn;
import org.apache.zookeeper.txn.SetDataTxn;
import org.apache.zookeeper.txn.TxnHeader;
import org.apache.zookeeper.txn.MultiTxn;

public class SerializeUtils {
	private static final Logger LOG = LoggerFactory.getLogger(SerializeUtils.class);

	public static void deserializeSnapshot(DataTree dt, InputArchive ia, Map<Long, Integer> sessions)
			throws IOException {
		int count = ia.readInt("count");
		while (count > 0) {
			long id = ia.readLong("id");
			int to = ia.readInt("timeout");
			sessions.put(id, to);
			if (LOG.isTraceEnabled()) {
				ZooTrace.logTraceMessage(LOG, ZooTrace.SESSION_TRACE_MASK,
						"loadData --- session in archive: " + id + " with timeout: " + to);
			}
			count--;
		}
		dt.deserialize(ia, "tree");
	}

	public static Record deserializeTxn(byte txnBytes[], TxnHeader hdr) throws IOException {
		final ByteArrayInputStream bais = new ByteArrayInputStream(txnBytes);
		InputArchive ia = BinaryInputArchive.getArchive(bais);

		hdr.deserialize(ia, "hdr");
		bais.mark(bais.available());
		Record txn = null;
		switch (hdr.getType()) {
		case OpCode.createSession:
			// This isn't really an error txn; it just has the same
			// format. The error represents the timeout
			txn = new CreateSessionTxn();
			break;
		case OpCode.closeSession:
			return null;
		case OpCode.create:
			txn = new CreateTxn();
			break;
		case OpCode.delete:
			txn = new DeleteTxn();
			break;
		case OpCode.setData:
			txn = new SetDataTxn();
			break;
		case OpCode.setACL:
			txn = new SetACLTxn();
			break;
		case OpCode.error:
			txn = new ErrorTxn();
			break;
		case OpCode.multi:
			txn = new MultiTxn();
			break;
		default:
			throw new IOException("Unsupported Txn with type=%d" + hdr.getType());
		}
		if (txn != null) {
			try {
				txn.deserialize(ia, "txn");
			} catch (EOFException e) {
				// perhaps this is a V0 Create
				if (hdr.getType() == OpCode.create) {
					CreateTxn create = (CreateTxn) txn;
					bais.reset();
					CreateTxnV0 createv0 = new CreateTxnV0();
					createv0.deserialize(ia, "txn");
					// cool now make it V1. a -1 parentCVersion will
					// trigger fixup processing in processTxn
					create.setPath(createv0.getPath());
					create.setData(createv0.getData());
					create.setAcl(createv0.getAcl());
					create.setEphemeral(createv0.getEphemeral());
					create.setParentCVersion(-1);
				} else {
					throw e;
				}
			}
		}
		return txn;
	}

	public static void serializeSnapshot(DataTree dt, OutputArchive oa, Map<Long, Integer> sessions)
			throws IOException {
		HashMap<Long, Integer> sessSnap = new HashMap<Long, Integer>(sessions);
		oa.writeInt(sessSnap.size(), "count");
		for (Entry<Long, Integer> entry : sessSnap.entrySet()) {
			oa.writeLong(entry.getKey().longValue(), "id");
			oa.writeInt(entry.getValue().intValue(), "timeout");
		}
		dt.serialize(oa, "tree");
	}

}
